Punch



I. F.- DOOLITTLE.

PUNCHl VAPPLICATION FILED JAN.5. 1920.

Patented Feb. 15, 1921.

fr?. i.

part obvious and in UNITED STATES PATENT OFFICE.

JOHN F. DOOLITTLE, OF FALFURRIAS, TEXAS, IASSI(5|].\1|'OIR TO THE CLEV-YELAND STEEL TOOL COMPANY, OF OLEVELAND, OHIO,

A CORPORATION OF OHIO.

PUNCH'.

Specification of Letters Patent.

Patented Feb. 15, 1921.

Application led January 5, 1920. Serial No. 349,631.

T o all whom it may concern i Be it known that I, JOHN F. DoonITTLE, a citizen of the United States, residing at F alfurrias, in the county of Brooks and State of Texas, have invented certam new and useful Improvements ,in Punches, of which the following is a specification.

This invention relates to punches. The object of the invention is to provide an improved construction for firmly securing a punching or similar tool to the reciprocating shaft, and which arrangement provides relatively large bearing surface `between the punching tool and'lts securmg parts, so as to reduce the liabllity ofl breakage of the tool which also insures accurate centering of the tool relative to the Work;

and which enables several tools of different sizes to be securely clamped to the same,

operating shaft with certainty of accurate centering of all of such tools.

Further objects of the invent1on are 1n part will appear more in detail hereinafter.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the drawings Figure 1 represents a sectional elevation of one form of the invention; Fig. 2 is a similar view, illustrating a different size of tool and bushing; ig. 3 is a plan view of a bushlng; F1g 4 is a sectional elevation* thereof on the line 1- 4, Fig. 3;.. Fig. 5 is a view similar to Fig. l, and illustrating another size of coupling nut; and Figs. G and 7 are vlews simi- 'lar to Fig. 4f yand illustrating additional bushings for use with the nut shown in Fi 5.

lgillustrates the reciprocating shaft of the' punchingmachine to which is secured the punching tool. 'Said shaft is threaded at 2 to receive the threads of the coupling nut 3 which is screwed upon the shaft forl securing thereto the punch 4. The couplmg nut 3 comprises an upper threaded portlon for engaging the plunger and a lower seat portion which receives the bushlng. In the drawings the punchis illustrated as provided rwithl an operating end 5 for punching holes, but it will of course be understood that the tool may have an operating end portion for setting rivets or performing other operations than punching holes.

The end of the shaft lor plunger 1 1s out as much as possible the area of different sizes to be secured to the same shaft. Preferably the arrangement is such that several punches, according to size, may be made from bar stock of different sizes so as-toreduce the cost for tool steel. This result is secured by Yproviding for each coupling nut 3 a series of bushings or ,seat members 7, the bushings shown in Figs. 1, 2 and 4 all being arranged for use with the same` coupling nut and being adapted to recelve punches of different sizes. The several bushings all have the same external shape. They are frusto-conical, having an outer conical surface 8 tapered'on a relatively acute angle, for example an angle of approximately 12 or less,` to the axis of the bushing. Other things being equal this angle will be more acute to thereby increase the bearing or seating surface between the bushingvand coupling nut, which nut has the inner surface of its opening tapered to fit with the outer surface of the bushings. The angle of inclination should not be so small that the parts will wedge together too tightly to be readily freed. This relatively long conilferent sizes of tools to be used with the same coupling nut and shaft. 'For example there will bel provided four to sixmore or less bushings externally tapered to tit the coupling nut 3 shown in Fig. 1, each of said bushings receiving a different size of tool.

I may also series of coupling nuts, all of which are ar-y ranged to thread upon-said shaft but which to correspond withv provide a given shaft with ay These nuts' will have central openings'of differentv sizes each adapted to receive a series of different bushings. F ig.` for example, shows `a coupling nut 3 adapted to receive the bushings illustrated in Figs. 5, 6 and 7, all of which are of the same external size and shape but are smaller than the bushing shown in Fig.l l. Thesev smaller bushings will receive tools of smaller sizes thanth first group or series of bushings. y

By using'aseries of lcoupling nuts and several series-of bushings each tool may have a head portion 10 not materiallydiffering in cross section'fro'm thef body portion of the tool. Therefore,'each tool can be constructed from standard bar stock of minimum size thereby reducing the'cost. i

Y WhatI claim is:v I

A1. In combination, a plunger, clamping means detachably -secured thereto and pro- -vided with an unbroken frusto-conical seat therein, and a punch having an unbroken fru'sto-conical surface engagingv said seat,

thetaper of said engaging surfaces havmg.

the same angle of inclination toward the cutting endof the punch and being uniform throughout.

2.In combination, a plunger, a coupling nut threaded thereon and provided 'with a frusto-conical opening therein, a .bushing seated in saidopeningeand conical linnen vand outer surfaces, and,l a punch having a frusto-conicalsurface seated infsaidbushing, the taper of all of-said frustconical 'surfaces having the same vangle, of

lfinclinationtoward the cutting end ofthe f punch and being uniform throughout.

l F3. In combination', a plunger, clamping means detachably-secured thereon and provided with an unbroken frusto-conical seat therein, the inclination of said seat being punch having a truste-conical surface seated in said bushing, the inclination of all of said frusto-conical surfaces being toward the cutting end ofthe punch, making an angle of approximately twelve degrees with the\ axis of said nut and being uniform throughout.

5. In combination, a plunger, a coupling nut threaded thereto and provided with a vfrusto-conical opening therein, a unitari1 frusto-conical bushingY having inner and outer inclined surfaces and seatedin said nut, the engaging surfaces of said nut and bushing having'the same and uniform inclinatlon throughout, and a punch having an inclined surface engaging the inner surface -\of said. bushing, the engaging surf'aes of' said punch and bushing having the same -and uniform inclinationl throughout, all. of said surfaces having their taper in a direction toward the cutting end of the punch.

In testimony whereof I aiix my' signature.

y Joint F, DOOLITTLE. 

